1. Field of the Invention
This invention relates generally to a testing system and method used for quality and performance test as part of an integrated manufacture and testing system. More particularly, this invention relates to an improved system architecture and method wherein the testing equipments are optimally distributed whereby the productivity of manufacture is increased because the tests are performed in parallel and the time required for maintenance and repair of the testing system is decreased.
2. Description of the Prior Art
The processing speed and the reliability of the on-line testing equipments are imposing ever more limitations on the productivity of a manufacturing line. This is caused by the facts that the number of tests to be performed for each single device are increased and meanwhile each of these tests are functionally more complicate while demanding more stringent accuracy in parameter measurements. Such trend is expected to continue and become even more intensified since the manufacture technology is moving toward a higher level of functional integration while aided by modern electronic technology, each function is now enabled to perform more complex processes. The bottle neck caused by the testing through-put must be resolved if high productivity with one-hundred percent quality assurance testing are to be achieved in a modern high-speed production line.
In response to technology's continuous movement to a high level of functional integration in manufacturing, a trend of `testing integration` also seems to appear in parallel. This trend of testing integration is aided in a great deal by the availability of testing computer which can automnate and schedule a plurality a tests in a single `testing station`. A typical testing station is disclosed in U.S. Pat. No. 4,807,161, entitled "Automatic Test Equipment" (issued on Feb. 21,1989 to Comfort et al.), wherein a test station is capable of performing a plurality of functional tests for the electrical printed circuit board (PCB) assemblies. The automatic test equipment (ATE) is constructed as the combination of a `programmable controller` configured as a micro-computer which has a plurality of selected interface modules. Each interface module includes hardware, i.e., different types of testing instruments, and software for automatically testing the PCB assemblies.
Comfort et al. assert, in U.S. Pat. No. 4,807,161, that the ATE, when configured as an integrated test station, has the advantage of allowing user more flexibility to perform a variety of tests by the use of multiple input and output. Nevertheless, such test configuration often becomes a productivity bottle-neck due to the fact that the multiple functional tests as performed by a single integrated test station is typically placed at the very end of a production line which often requires long test time. As a matter of fact, the more tests the ATE performs the longer testing time it requires and the higher is the probability that the products have to wait in line for the `final` testing.
In addition to the longer time required for performing the multiple tests by a single test station, the computer-based testing controllers, implemented with software and hardwire, are quite complex and also expensive. Due to its complexity, once there is any malfunction or performance abnormality, the diagnosis and repair of the integrated ATE can be a very time consuming process. The limitation of this prior art technology is further compounded by the fact that once the integrated ATE stops its normal operation the productivity of the entire production line may likely drop to zero unless there are a redundant or backup ATE available for immediate replacement.
In U.S. Pat. No. 4,894,829, entitled `Comprehensive Design and Maintenance Environment for Test Program Sets" (issued on Jan. 16, 1990 to Monie et al.) wherein a similar ATE system is used. More software features are built in for the testing system to perform a variety of tests aided by database and graphic display for better user interface. The test software even has features for test scheduling whereby a series of tests can be conducted in sequence as scheduled. However, such system can be even more complex and more expensive. Furthermore, it suffers the same difficulties and limitations as encountered by the aforementioned invention disclosed by Comfort et al. Furthermore, the tasks of diagnosis and repair become more difficult once a system problem occurs since the testing system now is much more complicate as it includes electronic hardware and associated software. Most likely, these tasks can only be performed by specially trained field service engineers. The adverse impact to the productivity of a manufacture line may be even more significant if such specially trained engineers are not immediately available.
Therefore, for those skilled in the art, there is still a need for a new and improved test configuration and method. Specifically, this new system and method for performing the multiple parameter testing should allow easy maintenance and repair of the test equipments. Such system should also capable of being optimized such that the online tests and the manufacturing steps can be streamlined to increased the productivity of a production line.
FIG. 1A is a block diagram showing a typical conventional multiple input/output ATE system 100 used to perform a plurality of functional tests on a manufactured product generally referred to as an unit under test (UUT) 105. The UUT 105 as shown is a power supply unit and the ATE system as shown is a Chroma-6000 ATS system. FIG. 1B is a corresponding perspective view of the ATE system 100 shown in FIG. 1A. The ATE system 100 includes a micro-computer 110 which controls the testing processes through a system controller 112 and a connected data-bus interface 114. The micro-computer also has a user interface station 116 which generally includes keyboard, monitor, printer, or plotter thus enabling an ATE operator to monitor and control the test processes.
The UUT 115 are activated by the energy generated by the AC and DC power supply units 120 and 122 and provided to the UUT 105, under the control of the system controller 112, via an extended measurement unit 118 to the input pins of the UUT 124. A plurality of test signals are received, under the control of the system controller 112, by different switch analyzer 130 from the output testing pins 132 of the UUT 105. The output test signals from the UUT 105 are then received and analyzed by the switch analyzers 130 and the computer 110. The quality of the product, e.g., a power supply unit, is certified and finally released for further processing based on the result of these multiple tests.
The ATE system 100 therefore more clearly illustrates that the prior art technique is limited by the fact that all the tests are performed by a single and very complex system in a strictly serial manner. As a result of that limitation, the process of these tests are more time consuming because no multiple tests are performed in parallel. Additionally, the combined ATE system becomes very complex and difficult to repair and maintain once a system malfunction occurs.